Objective: To determine the effect of tetramethylpyrazine (TMP) on the expression of migration inhibitory factor (MIF) in acute spinal cord injury (ASCI) in rats.
Methods: Allen's weight-drop method was used to establish a rat model of ASCI at T10. A total of 110 adult SD rats were divided into a sham operation group (group S, n=10), a control group (group C, n=50), and a TMP group (group T, n=50). Spinal cord functionality was measured by a modified Rivilin loxotic plate degree, BBB score, and combined behavioral score (CBS) at 1, 3, 5, 7, 14 and 21 d postoperatively. The injured spinal cord tissue samples were harvested at 1, 3, 6, 12 h and 1, 3, 5, 7, 14, 21 d postoperatively (n=5 at each time point) and used to prepare continuous histological sections, in which the expression of MIF was analyzed by immunohistochemistry.
Results: The degree in group T measured by modified Rivlin loxotic plate test after the ASCI was significantly higher than that in group C at 7, 14, and 21 d (P<0.05). BBB score in group T was significantly higher than that in group C at 5, 7, 14, and 21 d after the ASCI (P<0.05). CBS score in group C was significantly higher than that in group T at 5, 7, 14, and 21 d after the ASCI (P<0.05). The significantly low number of MIF positive cells was shown in group T when compared with that in group C at 12 h and 1, 3, 5, 7 d after the ASCI (P<0.05). As time passed, there was negative correlation between modified Rivlin loxotic plate degree and MIF expression and also between BBB score and MIF, and there was positive correlation between CBB score and MIF expression.
Conclusion: TMP has protective effect after the ASCI, and may promote the repair of injured spinal cord tissues. TMP may decrease the MIF expression in cells after the ASCI.